Let us consider the linear integer programming problem:

A := Matrix([[1, 7, 1, 3], [1, 6, 4, 6], [17, 1, 5, 1], [1, 6, 10, 4]]):
 n := 4; z := add(add(A[i, j]*x[i, j], j = 1 .. n), i = 1 .. n):
restr := {seq(add(x[i, j], i = 1 .. n) = 1, j = 1 .. n), seq(add(x[i, j], j = 1 .. n) = 1, i = 1 .. n)}:
 sol := Optimization[LPSolve](z, restr, assume = binary);

Error, (in Optimization:-LPSolve) no feasible integer point found; 
use feasibilitytolerance option to adjust tolerance

sol1 := Optimization[LPSolve](z, restr, assume = binary, feasibilitytolerance = 100, integertolerance = 1);

Error, (in Optimization:-LPSolve) no feasible integer point found;
 use feasibilitytolerance option to adjust tolerance

That was OK in Maple 16, outputting

.

The bug in one of the principal Maple commands lasts since Maple 2015, where the above code causes "Kernel connection has been lost". The SCRs about it were submitted three times (see http://www.mapleprimes.com/questions/204750-Bug-In-LPSolve-In-Maple-20151).

This is simplified from a larger example.  I never saw Maple exit from a numercal calculation.

> 123456789 ^ 987654321:
Execution stopped: Stack limit reached.

Process Maple R2016 exited abnormally with code 158

> kernelopts(maxdigits);
                                  38654705646

> lprint(123456789. ^ 987654321.);
.4339566080e7991619731

kernelopts(memusage) shows about 2~3 meg bytes used.

The system has 16G Ram.  16G swap.

Seems like something maple should have caught.

Try solve 

restart; with(PDEtools);
U := diff_table(u(x, y, z));

pde[1] := x*y*U[z]+x*U[x]+2*y*U[y] = 0;

bc[1] := eval(U[], z = 0) = x^2+y^2;
sys[1] := [pde[1], bc[1]];
pdsolve(sys[1])

Maple nothing returned. Where my mistake ?? Thank you.

I would like to see the list of metrics recognize by Maple with their acornym.  For example,:

>Setup(coordinates = spherical, metric = kerr)

What can i do in this case? I,m traying solve a system of non linear equation like this, i want to know Rs and Rsh:

I have the following fuction in Laplace domain,

restart:with(plots):with(inttrans):

u:=Pi^4*s3^(alpha-1)/((s1^2+Pi^2)*(s2^2+Pi^2)*(-s1^2+Pi^2*s3^alpha-s2^2))-Pi*s1*s2^(alpha-1)/(s3*(1+s2^alpha)*(-s1^2+Pi^2*s3^alpha-s2^2))-Pi*s1*s2^(alpha-1)/(-s1^2+Pi^2*s3^alpha-s2^2);

Where, s1, s2, s3 are the Laplace variables.

x1:=invlaplace(u, s1, x);

This worked. But the next two doesn't work.

y1:=invlaplace(x1, s2, y);

uu:=invlaplace(y1, s3,t);

Even, I tried to plot the unevaluated invlaplace but no luck.

alpha:=1:t:=1:
plot3d(uu,x =1..2, y=1..2);
 

Am I missing something?

Hi

I have an ODE which is based on a seperate function, and I would like to make a plot with the information

dsolve([diff(X(W), W) = (0.536000000000000e-3*(1-X(W)))*(1+X(W)), X(0) = 0], numeric)

and

C_A:= C_A0*(1-X(W))*(1+X(W))

which has been used as part of the ODE.

I would really like to plot C_A as a function of W. I have no problem plotting X as a function to W using odeplot. Ideally I would like to plot C_A and X vs W in the same plot.

Regards

I have a document containing notes from my past semester, which will not open properly. When i try to open up the document maple asks if i want to retrieve the content as plain text, 2D-math or maple input. The document is written in document mode and contains both text and 2D math. When I try to open it in plain text, maple gives me nothing, and with the two other options, maple is just loading forever. Can anybody help me retrieve the content og fix the document?

Noter_til_matematik_1.mw

I am working with Euler's eqns. of motion. So want to animate the solution. I could do a simple set of spheres along the x, y, z axes  that represent the body or use an imported STL file.  Looking for some guidance on how to approech this. I can import an STL ok. How do I give it an xyz set of axes and then rotate/move these in an inertial frame? I have the equations and solutions already. A reasonable example would be adding an STL of a pendulum to http://www.mapleprimes.com/questions/220957-Non-Simple-Harmonic-Pendulum-Motion#answer235955  to Preben's animation response to a recent post  I placed.

how i can save results on text file from pdsolve?

thanks

maple11.mw
 

Download maple11.mw

Hello everyone, I use physics package and I input:

with(Physics)

Setup(mathematicalnotation = true)

Coordinates(X)

Setup(tensors = A[mu](X))

PDEtools:-declare(A(X))

PDEtools:-declare(p0(X), pm(X), pp(X), pt(X), Un(X), Ucn(X))

pt := proc (X) options operator, arrow; Matrix(2, 2, [[p0(X), sqrt(2)*pp(X)], [sqrt(2)*pm(X), -p0(X)]]) end proc

U := proc (X) options operator, arrow; Matrix(2, 2, [[1, 0], [0, 1]])+I*pt(X)*(1/f)-pt(X)*pt(X)*((1/2)/f^2) end proc

Ucn := proc (X) options operator, arrow; Matrix(2, 2, [[1, 0], [0, 1]])-I*pt(X)*(1/f)-pt(X) . pt(X)*((1/2)/f^2) end proc

And after that I write:

Trace(-LeviCivita[mu, nu, rho, sigma] . Ucn(X) . ((1/6)*e*A[nu](X)+M5*KroneckerDelta[nu, 0]) . Matrix(2, 2, [[1, 0], [0, 1]]) . Uсn(X) . d_[rho](Un(X)) . Uсn(X) . d_[sigma](Un(X)))

But I get an error:

Error, (in unknown) invalid subscript selector

Thanks for the help.

Hi,

I have a Maple code which produces an output plot for a first order differential equation,

nde := evalf(subs(npar, de));
nds := dsolve({nde, sigma(0) = -1e-8}, sigma(t), type = numeric);
acc_nds := (sig0, ae, re) -> dsolve({nde, sigma(0) = sig0}, sigma(t), type = numeric,
method = lsode[backfull], abserr = ae, relerr = re, maxfun = 0, ctrl=Ctrl);

odeplot(acc_nds(-0e-7, 1e-13, 1e-13), [t, sigma(t)], t = 0..2);

This produces the outputplot that I need for sigma(t). I need to produce a outut for d(sigmat)/dt, and how can this be done? what is the command I should use?

Additionally, how can i get the data set out of the polt in to a excel file or a text file?

I am quite new to maple, so i expect your kind support

Thanks

Hello! I try to make friends physics package and matrixes. But I am faced with difficulties. To be more specific, to consider a code:

with(Physics):
Setup(mathematicalnotation = true);
Coordinates(X);
Setup(tensors = A[mu](X));
PDEtools:-declare(A(X), p0(X), pm(X), pp(X), pt(X), U(X), m5(X))

And then I create a matrix:

pt := proc (X) options operator, arrow; Matrix(2, 2, [[p0(X), sqrt(2)*pp(X)], [sqrt(2)*pm(X), -p0(X)]]) end proc;

It displays as:

Why do p0, pp, pm become function only one variable x1?

Interestingly that maple understands the next matrix:

Nevertheless even for function only one variable derivative works fine:

And I can construct more complicated functions:

But why is only one variable?

Edited.

Fellas

I'm wondering how to produce the graphic in the

https://en.wikipedia.org/wiki/Lazy_caterer's_sequence.

my attempt:
caterers.mw

I will try to explain with an example, lets say i have to solve 2 equations with 2 unknowns

P := solve({3*y+x, 2*x+3+y})

I would then like to do P[1] and P[2] to get the values, but instead it gives me "x=-9/5" which make me unable to use it for things like

P[1] + P[2]

Hope you all understand, and thanks for taking your time to read my problem